A crisp Italian style meringue with a clementine custard filling.
Preheat the oven to 145'C.
Make the macaroon shells: place the ground almonds and the icing sugar in a food processor and mix to give a fine, lump-free powder.or use a fine sieve.
Place the water and the caster sugar in a saucepan and heat to 118'C. Whilst this mixture is heating, whisk 75g of egg whites. Once the sugar has reached 118'C, add it to the egg whites and whisk until the mixture cools down. Add the food colouring and mix gently.
Add the remaining egg whites to the icing sugar and almond mixture and mix well until you obtain a paste , Add a spoonful of the meringue mixture at the time and fold it in. Once the mixture reaches the ribbon stage, place it in a piping bag and then pipe the macaroons on to a lined baking sheet. Gently tap the baking tray down on to the work surface. Transfer to the oven and cook until the macaroons feet are created, after that keep on opening the oven door every minute or two to turn the macaroons. Macaroons are ready when they don't stick in the paper anymore , it'll take around 12/15min.
Zest and juice the clementines and lemon into a small pan along with the sugar and the eggs and extra yolk.
Bring gently up in temperature, constantly whisking, to keep the eggs from scrambling.
Once thickened, remove from the heat and whisk in the knob of butter, lay flat on a tray with cling film laying across the top and put in the fridge until cooled and set.
«This can be done over a double boiler as well. It takes a lot longer but will have less chance of the curd scrambling»